Errcode:2006 Errmsg:mysql Server Has Gone Away

[Brad]

Last evening, after upgrading MySQL from 5.0.84 to 5.1.40, MONyog began to induce failed logon attempts to the physical server. The server ID/PW was not changed in this process, however, it began failing about 4 hours after the MySQL upgrade. After disabling, rechecking all passwords (inputting again for assuredness), and then reenabling, all seemed to be functioning again (all connectivity checks passed). I was also running MONyog 3.5 as of last evening, and upgraded to MONyog 3.6.2 this afternoon as part of the remediation. The issue was abated prior to the upgrade, but thought I should mention none the less.

After this, I began reviewing the logs for MONyog. The issue I encountered, which locked me out of the server (Brute Force protection) was resolved, and no longer throwing logon failures. I have, however, noticed that every time Data Collection runs, the following error is being logged:

Example:

[3.62] [2009-12-20 16:34:20] lib/webyog/src/ymysql.cpp(392) ErrCode:2006 ErrMsg:MySQL server has gone away

This occurs every single time the Data Collection routine executes, and according to the logs, has been since the day I first installed the demo version, and continued from when I purchased MONyog last month.

Any idea as to why this is occurring?

This would seem to indicate that the data is not being updated, however, when I look at the Dashboard, MySQL Availability shows all green, and the other data collection points being gathered are also populating. The latter being said, MONyog is obviously connecting to the MySQL dB, yet the error is being thrown anyway.

What can I do to eliminate this error from occurring?

[Brad]

In doing a little more diggin, I cannot even locate a file named “ymysql.cpp” on the server (find / -name ymysql.cpp) nor can I locate a directory named “webyog”.

[Sayan Chaliha]

Hey Brad,

“MySQL server has gone away” is generated by the MySQL client library (libmysql) that we use in MONyog. There are several reasons as to why this error occurs. I'd refer you to this blog post (note that it is in two parts), but in brief:

— This error occurs when MySQL does not respond to MONyog's (or any client's, for that matter) query after a successful connection;

— The most common cause in this case is that MySQL's 'wait_timeout' variable is set lower than MONyog's data collection interval. Use the following query to determine your server's 'wait_timeout':

Code:

SHOW GLOBAL VARIABLES LIKE 'wait_timeout';

— An immediate resolution to your problem would be to increase the 'wait_timeout' of your server:

Code:

SET GLOBAL wait_timeout=28800;

28800 implies 8 Hrs, which is the default in most MySQL distributions.

— Note that this error doesn't affect MONyog's functionality nor that of MySQL's.

Also, it is improbable that you'd find 'lib/webyog/src/ymysql.cpp' or any other MONyog source file. The error log records the exact line number of the source file that generated the error so that our debugging team knows exactly which part of the source code registered the error.

[Brad]

Well, adjusting the wait_timeout parameter in my.cnf seems to have remedied the scenario. Thanks for you assistance.

I would never leave the value set to 8 hours, however, adjusting it to exceed the Data Collection interval abated the error.

Thanks again.

[Author]

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